I drill most inch holes using either fractional sizes or drill bits with letter and numbers for threaded holes or clearance holes for machine screws. But mostly I have to drill true metric sizes - the nearest decimal equivalent just doesn't do the trick. Your standard home center doesn't usually have metric drill bit sizes - you usually have to order them or pay a fortune upon delivery. At home. So this set has been a real godsend for some of the tasks I'm doing more and more often. Bits are standard - thanks to the titanium coating, they work just as well as fractional and decimal counterparts. It's also a good idea to have a few of each size. I am very happy with these drills.